Multiple myeloma and Waldenstrom's macroglobulinemia are two hematological cancers that affect approximately 45,000 and 1,500 people, respectively, in United States each year. Although both disorders are often treated using, e.g., chemotherapy alone or in combination with a bone marrow transplant, the prognosis for patients afflicted with one of these disorders is generally poor. Efficacious therapies and/or prophylactic regimens are therefore urgently needed.